Drop build-dependencies used for the Google Cloud Print backend

The service required by this backend was shut down, so the printing
backend is no longer useful and was removed by upstream.

debian/control

@@ -27,9 +27,7 @@ Build-Depends: adwaita-icon-theme <!nocheck>,
                libgirepository1.0-dev (>= 1.39.0),
                libglib2.0-dev (>= 2.57.2),
                libharfbuzz-dev (>= 0.9),
-               libjson-glib-dev,
                libpango1.0-dev (>= 1.41.0),
-               librest-dev,
                librsvg2-common <!nocheck>,
                libwayland-dev (>= 1.14.91) [linux-any],
                libx11-dev,

debian/control.in

@@ -27,9 +27,7 @@ Build-Depends: adwaita-icon-theme <!nocheck>,
                libgirepository1.0-dev (>= 1.39.0),
                libglib2.0-dev (>= 2.57.2),
                libharfbuzz-dev (>= 0.9),
-               libjson-glib-dev,
                libpango1.0-dev (>= 1.41.0),
-               librest-dev,
                librsvg2-common <!nocheck>,
                libwayland-dev (>= 1.14.91) [linux-any],
                libx11-dev,

debian/rules

@@ -99,7 +99,6 @@ configure_flags_deb = \
 	--enable-man \
 	--enable-shared \
 	--enable-introspection \
-	--enable-cloudprint \
 	--disable-static \
 	--enable-installed-tests
 
@@ -124,7 +123,6 @@ configure_flags_udeb = \
 	--disable-wayland-backend \
 	--enable-x11-backend \
 	--disable-introspection \
-	--disable-cloudprint \
 	--disable-colord \
 	--disable-xcomposite \
 	--disable-xdamage \